The invention relates to an electrical quick-thawing apparatus for quickly thawing frozen liquids, for example injection or infusion solutions, comprising a transmission plate and a clamping and heating device for receiving a container containing the frozen liquid, especially a syringe or ampule, which clamping and heating device includes an electrical heating unit with at least one heating surface and at least one temperature sensor measuring the temperature at the outer wall of the container. Also included is an electrical control device with a temperature governor whereby the temperature sensor with its output terminal is connected to the temperature governor and with a control circuit which is connected with an outlet terminal to a switching device for controlling the heating unit and controls it depending on signals of the temperature sensor connected to the input terminal of the control circuit and the signals of a set point adjuster.
In clinical practice it is common to administer pharmaceutical products which are supplied by the pharmaceutical industry in standard concentrations and standard volumes and are diluted with carrier solutions to a patient-specific concentration for administration. Since these individually prepared preparations are often used in long-term therapies, the patient-specific active mixture is produced in a respectively large total volume. The individual portions that are to be administered in each session therefore must be filled into syringes or other containers and subsequently frozen.
Only in this manner is it possible to preserve the generally thermally instable active substances over the required time period.
One problem of this accepted and widely used conventional preservation method is that the individual samples require a relatively long thawing time. This is very cumbersome especially when the exact point of time of administration of the ampule volume cannot be exactly predetermined. Even though for the individual patient a time schedule for administering the substance volume is available conventional to first take a blood sample of the patient in order to determine according to the analysis results whether and when the next substance volume is to be administered. This approach thus often results in schedule changes and also in the loss of the already thawed active substance.
In order to avoid this time and cost problem, there is the urgent need to provide a quick-thawing apparatus and a method which allows to thaw the active substance volume quickly.
The prior art discloses microwave thawing devices for frozen liquids which are heated by microwaves of frequencies between 2,425 and 2,475 GHZ. However, these devices have the disadvantage that certain areas of the frozen liquid, due to focusing of the radiation, are overheated so that a uniform heating of the frozen liquid does not take place. The heating of the frozen liquid only in certain areas can result in damage to the ingredients or active substances of the liquid so that chemical modification of the ingredients or the active substances must be assumed. It is apparent that the thawing of infusion solutions or injection solutions in syringes or ampules with conventional microwave thawing devices must be avoided because a chemical modification of the medication as well as denaturation of vaccinations, proteins or serum within the infusion or injection solutions cannot be reliably prevented.
Furthermore, it should be noted that because of the damage of the medically active ingredients of the injection and infusion solutions their medical and therapeutic activity decreases with increasing thawing time. Furthermore, it has been shown that the resulting decrease of medical activity requires a higher dosage and thus a higher concentration of the medically active ingredients in the infusion and injection solutions so that more material must be used, thereby increasing substance use and costs.
Furthermore, the health-detrimental effect of the prior art methods for quickly thawing, such as methods employing microwaves, resulting in hot spot formation, or the use of hot flowing water etc., which may cause modified active substances or contamination with illness-causing microorganisms must be mentioned, whereby their disadvantageous long term effects have been elucidated only partially, but certainly considerable stress on the organism during the decay phase within the patient's body will result.
Also, it has been shown that the use of turntables in microwave thawing devices cannot ensure uniform heating of the frozen injection solutions especially in elongate containers, such as syringes or ampules used widely in the medical field, because, despite the rotation of the turntable causing the container to leave the focusing area, a local overheating of the frozen liquid can be so great that the aforementioned damages of the medication contained in the infusion and injection solutions will occur, i.e., no low-impact thawing will be performed.
Furthermore, the conventional thawing of frozen injection solutions contained in syringes by holding the syringes under hot flowing water, may result in contamination of the liquid by microorganisms which may be forced or introduced by the water jet from the exterior into the gap between the syringe plunger and the syringe body.
The prior art methods for thawing, for example, by heating the active substance volume by using microwave devices, subjecting the syringes to flowing hot water, should therefore be avoided for reasons of thermal instability of the active substances to be administered as well as the lack of required sterile handling of the medium. For these reasons, it is advisable to thaw the ampule at room temperature until thawed resulting however in the great disadvantage of a long thawing time and a need for greater concentration of the active material in the medium because of the expected decomposition of the heat-sensitive active substance.
Moreover, the degree of decomposition of the heat-sensitive active substance can only be estimated and is not exact because the thawing time depends on the actual room temperature which subject to fluctuations so that higher or lower active substance amounts than expected may be administered, a situation which can result in stress to the patient.
Another possibility, e.g., manually heating syringes by one's palm cannot prevent contamination by microorganisms. Furthermore, thawing by hand takes a long time whereby only injection solutions of a volume of 1 ml to 2 ml can be thawed within 5 minutes. However, in hospitals during daily routine work, in emergency rooms or at accidents on site, it is urgently needed and life saving to be able to quickly thaw infusion and injection solutions which are supplied, ready to be administered, in freezers.
Especially manual thawing by the user, which is suitable for only minimal liquid volumes, results in greater time expenditure because the user cannot perform at the same time other activities in hospitals, intensive care units, emergency situations etc., and this results in higher personnel costs.
Since manual thawing of larger amounts of injection solutions to be administered regularly hospitals is very time consuming, especially since the heat capacity of the palm of the user is minimal and the exchange or mixing of cold and warm liquids is time consuming, the conventional methods for thawing as used in hospitals, intensive care units, and emergency rooms are unsuitable and should not be used especially in view of the lack of sterile handling.
It is an object of the present invention to eliminate the aforementioned disadvantages of the prior art. Furthermore, it is desirable to provide a quick thawing apparatus which shortens the thawing time by a multiple and at the same time ensures a careful and sterile treatment of the active substances. Furthermore, it should be possible to provide the quick-thawing apparatus with a simple mechanicdevice in ordertoensure high transportation safety and also minimal maintenance. Also, the quick-thawing apparatus should be embodied such that a quick and sufficient cleaning and sterilization of its components is possible in order to avoid spreading of infection diseases in hospitals.